1. Field of the Invention
The present invention relates to an apparatus for generating a stereoscopic image and which is capable of generating a stereoscopic image for presenting a stereoscopic screen display based on two-dimensional image information as well as to a method for generating a stereoscopic image.
2. Description of the Related Art
When a man sees an object with both eyes, the position of the object image reflected on the retina of the left eye is different from the position of the object image reflected on the retina of the right eye. The dislocation of the object image in both eyes causes the man to feel the depth of the object. In order to obtain a stereoscopic image on a monitor screen, it is necessary to obtain image information which dislocates the object image reflected on the retina of the left eye and the object image reflected on the retina of the right eye from each other.
To this end, the following method is carried out conventionally. That is, stereoscopic image information is obtained as follows. The stereoscopic image information comprises two image information. One is used for the right eye for forming an object image on the right eye's retina according to the visual point thereof. The other is used for the left eye for forming an object image on the left eye's retina according to the visual point thereof. The right eye sees the image for the right eye based on the image information for the right eye and the left eye sees the image for the left eye based on the image information for the left eye.
Conventionally, the following two methods are performed to obtain a stereoscopic image based on the stereoscopic image information:
According to a first method, a camera 1 for the left eye and a camera 2 for the right eye pick up the image of a three-dimensional object as shown in FIG. 16 with the visual points differentiated from each other. The image information for the left eye obtained by the camera 1 and the image information for the right eye obtained by the camera 2 are inputted to a video recorder 3.
The video recorder 3 synthesizes the image information for the left eye and the image information for the right eye so as to generate a video signal. The video recorder 3 generates the video signal of an odd number field, based on the image information for the left eye and the video signal of an even number field, based on the image information for the right eye. The video signals thus generated by the video recorder 3 are displayed on a monitor 4 comprising a cathode ray tube (CRT).
An operator sees an image displayed on the monitor 4 through liquid crystal shutters, of liquid crystal shutter glasses 5, which opens and closes under the control of the video recorder 3. In synchronization with the vertical synchronizing signals, the video recorder 3 closes the liquid crystal shutter on the right eye side when odd number fields are displayed and the liquid crystal shutter on the left eye side when even number fields are displayed.
Based on the image displayed on the monitor 4, the operator can see the image for the left eye with the right eye and the image for the right eye with the left eye almost simultaneously. Thus, the image position of the object reflected on the retina of the left eye is different from the image position of the object reflected on the retina of the right eye. Therefore, the operator watches a stereoscopic image on the monitor 4.
According to a second method, the information of each position of an object which is to be stereoscopically represented is indicated by data, and the data is inputted to a stereoscopic image processing section 6 as shown in FIG. 17. Then, based on the data, the image processing section 6 finds a stereoscopic image information comprising image information for the left .eye obtained when the object is seen from the visual point of the left eye and image information for the right eye obtained when the object is seen from the visual point of the right eye. The digital image information for the left eye and image information for the right eye are converted into analog image information so as to display the image for the left eye and the image for the right eye on a monitor 7 alternately, similarly to the first method.
Thus, the operator sees the image for the left eye and the image for the right eye alternately displayed on the monitor 7 through liquid crystal shutter glasses 8. Thus, the object viewed by the operator looks stereoscopic.
The above-described conventional method for obtaining a stereoscopic image based on the stereoscopic image information comprising the image information for the left eye and the right eye has, however, the following problems.
That is, according to the first method, it is necessary to form a three-dimensional object so that the object image is taken by the camera 1 for the left eye and the camera 2 for the right eye thus requiring going to the object location so as to photograph an object by the cameras 1 and 2. As such, much time and labor are required to form stereoscopic image information serving as a means for stereoscopically displaying for example, a landscape of a foreign country on the screen.
According to the second method, it is necessary to input the data of a three-dimensional object which is to be stereoscopically represented on the screen to the image processing section 6. However, in order for the image processing section 6 to obtain complicated image information for the left and right eyes, for example, the information of a landscape image, it is necessary to generate a large number of data of three-dimensional objects and input them to the image processing section 6. Thus, a stereoscopic image displayed on the screen by this method is not favorable.